val remove: string -> unit
val exists: string -> bool
-val resolve: string -> string
+val resolve: ?must_exists:bool -> writable:bool -> string -> string
(* val get_attrs: string -> Http_getter_types.prefix_attr list *)
val is_read_only: string -> bool
val is_legacy: string -> bool
+val is_empty: string -> bool
val clean_cache: unit -> unit
+val activate_system_mode: unit -> unit
+val list_writable_prefixes: unit -> string list